Researcher Vianney Nguyi Keating has turned mangosteen waste into an innovative energy storage solution by developing a new technology to produce activated carbon used in supercapacitors.
This technology represents a promising scientific breakthrough that could transform how we manage agricultural waste, while simultaneously enhancing the efficiency of renewable energy technologies.
Supercapacitors are a type of energy storage cell that functions similarly to batteries, but differ in their operating mechanism and speed. They can charge and discharge energy within seconds or minutes, unlike batteries, which discharge energy over a longer period. This makes them ideal for applications that require rapid power bursts, such as camera flashes, smartwatches, and portable car starters.
Supercapacitors are typically made from electrodes based on activated carbon, which can be extracted from biomass waste such as fruit peels. This is where Keating's contribution came in, using mangosteen peels to develop a simpler and more efficient method for producing this carbon.
Keating, a postdoctoral fellow at the iThemba Laboratories, developed a straightforward method for converting mangosteen peels into highly porous activated carbon by mixing the dried peels with potassium carbonate and heating them directly to 700°C, without the need for a preheating step as in conventional methods.
This method reduces electricity consumption, lowers costs, and speeds up the production process, making the technology suitable for large-scale commercial applications. Just 3 to 5 kilograms of fruit peels are sufficient to produce hundreds of supercapacitors.
The benefits of this technology are not limited to the industrial aspect, but extend to environmental and economic benefits. Instead of disposing of fruit peels in landfills, they are used as raw material for producing highly efficient energy storage devices. Supercapacitors also contribute to supporting the stability of renewable energy grids by absorbing excess solar or wind energy and releasing it when needed.
Although the market for supercapacitors is still limited, demand for them is growing rapidly, especially in areas such as electric vehicles, clean energy systems, and consumer electronics.
Other research also shows the potential of using citrus peels to produce activated carbon.
Keating points out that Africa has a great opportunity to benefit from this technology, especially since mangosteen trees grow abundantly across large areas of the continent. Fruit processing plants could establish small facilities to convert their waste into activated carbon and supply it to energy storage industries.
To achieve this goal, Keating stresses the need for government and private funding, the provision of infrastructure and equipment, and the training of local talent.
